DE Unit 3: AOI Design

Designing combinational circuits using And/Or/Inverter logic

AOI DESIGN OVERVIEW

This unit is really the start to our formal learning of digital electronics. The first two units were meant to get you familiar with various components and tools of digital electronics; now we get to start with the basics of the circuit design process and develop our own circuits. As we progress, we’ll follow the Circuit Design Process:

  • Define the problem (inputs and outputs)
  • Create the truth table
  • Write the AOI logic expression
  • Simplify the AOI logic expression if we can
  • Draw the AOI circuit diagram
  • Simulate in Multisim to test
  • Build on the breadboard to test and confirm

This process is the process we’ll use throughout the year to design our own circuits.  We’ll learn various tools to enhance the process and make some things happen quicker, but the basics of the process will remain the same. In this unit, you’ll work through the process in three main steps.

  1. STEP 1: Learn how to create truth tables from situations and how to write logic expressions
  2. STEP 2: Practice creating AOI circuit diagrams by hand and in Multisim
  3. STEP 3: Apply this knowledge in the solution to a voting problem

When you’re done, you’ll have a good understanding of the circuit design process and what needs to be done to design and build a working circuit as a solution to a real problem.

PART 1: LOGIC EXPRESSIONS

(20 pts) About 3 days

Our unit starts with the basics of truth tables and turning real-world problems into abstract mathematical expressions. The logic expressions we create here by hand will be able to be turned into working electronic circuits easily!

PART 2: LOGIC IMPLEMENTATION

(20 pts) About 3 days

As we continue our study of AOI logic, we now turn our attention to converting logic expressions into actual circuit diagrams.  By considering And, Or, and Inverter (negation) functions, it’s a pretty simple step to take a logic expression and draw the circuit diagram from it.  These can then be created in Multisim to confirm they work properly!

PART 3: MAJORITY VOTE

(30 pts) About 3 days

The last part of this unit asks you to complete the circuit design process for a voting system.  You’ll turn the word problem into a truth table, turn that into a logic expression, draw the circuit, simulate it in multisim, and then breadboard it.  The entire circuit design process!

Part 1: Logic Expressions

Become fluent in converting between AOI circuits, truth tables, and logic expressions
Combinational Logic Overview

The first part of this unit focuses on understanding Truth Tables.  Truth Tables are ways for us to formally organize the possible on/off (1/0) combinations of inputs and what that should translate into for outputs. The circuit design process starts with the development of a truth table because that will give us the organization we need to write a logic expression.  As you work through this first part of the unit, most of the work will be hand-written as you convert truth tables into logic expressions and vice-versa.

GRADING & PROCESS

Watch the Combinational Logic Overview and the Truth Tables to Logic Expressions presentations.  Take a full page of notes on constructing truth tables and writing expressions from them.

  Complete the Truth Tables to Expressions Assignment.

 Watch the presentation on Logic Analysis, taking careful notes on how to turn an AOI circuit into a truth table.

 Complete the AOI Circuits to Truth Tables Assignment.

 Have Mr. Benshoof approve your notes and completed Assignments.

Truth Tables to Logic Expressions
AOI Logic Analysis
AOI Overview

What’s Due In Part 1: Logic Expressions

  • Truth Table Notes
  • Truth Table to Expressions Assignment
  • Logic Analysis Notes
  • Circuits to Truth Tables Assignment
  • Mr. Benshoof’s Approval

Here’s what’s due in Part 1: Combinatorial Logic

  1. Good notes on Truth Tables to Logic Expressions
  2. Complete the Truth Tables to Expressions Assignment
  3. Careful notes on the presentation on Logic Analysis
  4.  Complete the AOI Circuits to Truth Tables Assignment.
  5. Have Mr. Benshoof approve your notes and assignments.

Part 2: Logic Implementation

Converting logic expressions into circuit diagrams so they can be simulated and built
AOI Logic Gate Reference
Expression Simplifying Rules

Our second part to the unit covers how to convert our logic expressions into actual circuit diagrams.  To do this, we’ll emphasize on how mathematical notation for multiplying and adding turns into the “Ands” and “Ors” or AOI logic.  We’ll also look at some Boolean Algebra rules that let us simplify logic expressions before making circuits.

GRADING & PROCESS

 Take a full page of good notes on AOI Implementation.  Make sure to emphasize when each of the three gates (And/Or/Inverter) are used!

 Complete the AOI Implementation Assignment.

 Use Multisim to simulate and then breadboard the required circuits from the AOI Implementation Assignment.

 Take a full page of careful notes on Simplifying Expressions – be sure to emphasize the different rules for simplifying.

 Complete the Simplifying Expressions Assignment.

 Have Mr. Benshoof check-off your notes, assignments, and circuits.

AOI Implementation

Simplifying Expressions

Simplification Overview

What’s Due In Part 2: Logic Implementation

  • AOI Notes
  • AOI Assignment
  • Multisim & Breadboarding
  • Simplifying Notes
  • Simplifying Expressions Assignment
  • Benshoof’s Check-off

Here’s what’s due in Part 2: Sequential Logic

  1. Take a full page of good notes on AOI Implementation.
  2.  Complete the AOI Implementation Assignment.
  3.  Build AOI circuits with Multisim and on the breadboard
  4.  Take a full page of careful notes on Simplifying Expressions.
  5. Complete the Simplifying Expressions Assignment.
  6. Have Mr. Benshoof check-off your notes, assignments, and circuits.

Part 3: Majority Vote

Work through the entire circuit design process to solve a problem
Majority Vote Overview

Our unit ends with a short project that has you work through the entire circuit design process in the creation of a solution to a small problem. In this “Majority Vote” problem, you’ll be asked to create a circuit that can tally votes for a small group of people following a specific set of criteria. You’ll need to start by creating a truth table from the problem situation, then writing an AOI logic expression and simplifying if possible. You’ll then convert your expression into a hand-drawn circuit, a Multisim simulation, and finally a breadboarded model.

GRADING & PROCESS

 Read through the Majority Vote problem carefully and watch the overview video.

 Create a Truth Table that describes the situation in your engineering notebook.

 Write an unsimplified logic expression from your truth table.

 Simplify your logic expression to get a final simplified logic expression.

 Have Mr. Benshoof confirm your simplified logic expression.

 Draw an AOI circuit diagram from your simplified logic expression

Simulate your AOI circuit in Multisim

 Breadboard your AOI circuit and confirm that it works

 Have Mr. Benshoof confirm your working breadboard circuit.

What’s Due In Part 3: Majority Vote

  • Truth Table & Expression
  • Mr. Benshoof’s Confirmation
  • Draw AOI Circuit
  • Multisim AOI Circuit
  • Breadboard AOI Circuit
  • Mr. Benshoof’s Check-Off

Here’s what’s due in Part 3: Majority Vote

  1. Create a Truth Table and simplified logic expression of the Majority Vote problem
  2.  Have Mr. Benshoof confirm your simplified logic expression.
  3.  Draw an AOI circuit diagram from your simplified logic expression
  4. Simulate your AOI circuit in Multisim
  5.  Breadboard your AOI circuit and confirm that it works
  6. Have Mr. Benshoof confirm your working breadboard circuit.

Double Check: Unit Expectations

Check what you need to have completed by the unit deadline
The purpose of this unit is to give you an experience working through the entire circuit design process from an original problem all the way through a working circuit. This process will be developed further as we learn new tools and strategies. For this unit, we’ll start our work in our engineering notebooks to calculate, plan, and design our circuits. We then get to work in the computer to simulate those circuits before breadboarding the actual working circuit.

Engineering Notebook:

(Part 1) You should have taken a full page of notes on Truth Tables to Logic Expressions.

(Part 1) You should have taken a full page of notes on Logic Analysis.

(Part 2) You should have taken a full page of notes on both AOI Implementation and on Simplifying Logic Expressions.

(Part 3) You should have made a Truth Table, logic expression, and simplified the expression for the Majority Vote problem in your engineering notebook.

 (Part 3) You should have drawn out your AOI circuit in your notebook before simulating.

Building & Making:

 (Part 1) You should have completed the Truth Tables to Expressions Assignment.

 (Part 1) You should have completed the AOI Circuits to Truth Tables Assignment.

 (Part 2) You should have completed the AOI Implementation Assignment.

(Part 2) You should have built AOI circuits in Multisim and on the breadboard to complete the AOI Implementation Assignment.

 (Part 2) You should have completed the Simplifying Expressions Assignment.

(Part 3) You should have built your Majority Vote Circuit in Multisim and confirmed that it works properly.

 (Part 3) You should have built your Majority Vote Circuit on a breadboard and confirmed that it works properly.

Checkpoints & Quizzes:

(Part 1) Benshoof should have checked-off your notes and completed assignments.

(Part 2) Benshoof should have checked-off your notes, assignments, and circuits.

 (Part 3) Benshoof should have confirmed your simplified logic expression.

 (Part 3) Benshoof should have confirmed your working breadboard circuit.